Package,especially for food products



United States Patent lnventor Appl. No. Filed Patented Assignee PriorityKarl Rune Persson Halmstad, Sweden 728,407

May 13, 1968 Dec. 29, 1970 Sprinter Pack AB Laholmsvagen, Halmstad,Sweden a corporation of Sweden May 17. 1967 Sweden PACKAGE, ESPECIALLYFOR FOOD PRODUCTS 4 Claims, 7 Drawing Figs.

U.S. Cl 229/31, 229/32 Int. Cl B65d 5/24 Field of Search 229/35, 31,

[56] References Cited UNITED STATES PATENTS 1,699,008 1/1929 Miller229/31(i) 3,298,593 l/l967 Stephenson.... 229/5l(is) 3,316,102 4/1967Doll et al. 229/3l(i) FOREIGN PATENTS 6,513,809 4/1967 Netherlands229/31 Primary ExaminerDavid M. Bockenek Attorney-Bauer and GoodmanABSTRACT: A package for food products comprising a single blank cartontray and a separate cover. The blank of the tray has corner portionsfoldable to three sectors forming a corner post of triangular crosssection in the erected tray. The wall panels have upper edge flapsconnected at their ends by connecting flaps formed as extensions of theupper ends of the central sectors of the post. The corner is sealed tothe frame formed by the edge flaps and the connecting flaps.

PATENTED DEE29 I976 SHEET 1 BF 3 FIG] PATENTEU DEB29 19m SHEET 2 UF 3PATENTED 05:29 I970 SHEET 3 BF 3" INVENTOR. Km! Rune Pensson PACKAGE,ESPECIALLY FOR FOOD PRODUCTS This invention relates to a package whichis primarily intended for food products, especially food products whichhave to be heated in the package by placing the package in ahighfrequency oven, a heating bath or on a heating plate. However, thepackage according to the invention may also be advantageously used forfood products which need not be heated, but nevertheless should beenclosed in a sealed package.

Hitherto, trays of plastic material or aluminum foil have been used forpacking ready-cooked food in so called portion packages. However, theplastic trays are usually made of a plastic material which does notwithstand heating in a highfrequency oven or on a heating plate up toabout 120 C. Trays of aluminum foil are electrically conductive and forthis reason they cannot be used for heating in high-frequency ovens.Another inconvenience of such trays is a certain difficulty to applythereto printed text or pictures, such as for instructions andadvertisement. All of these inconveniences can be avoided if the tray ismade of carton material which withstands temperatures up to usualheating temperature of about 150 C. and in addition thereto can bereadily provided with printed text and pictures.

In accordance therewith the object of the invention is to provide acarton package of sufficient tightness, strength and stability so as tobe able to be heated in an oven or on a heating plate and which is easyto open and sufficiently rigid to be used itself as a dish or plate fromwhich food can be eaten, if desired. Further, the package should beerected from a blank which may be mechanically erected and sealed.

For this purpose the invention embodies a carton tray which can bemechanically erected so as to form a fluid-tight tray. The tray iserected from a blank which at least on one side has a fluid-tightplastic coating which is adapted to be sealed and withstands heating toabout 150 C., such as polypropylene. In order to obtain fluid-tightcorners a blank is used which by fold lines is subdivided into a bottompanel and four wall panels which at their ends are connected to eachother by corner portions which by means of fold lines are subdividedinto three sectors, a central sector and two lateral sectors, extendingfrom a common apex at the adjacent corner of the bottom panel, whereineach lateral sector is in contact with the adjacent wall of the erectedtray and together with the central sector forms a corner post oftriangular cross section. Such a tray which is known per se is devisedaccording to the invention with supplementary details in the mannerindicated in the annexed claims in order to form, together with a cover,the package according to the invention.

Two suitable embodiments of the package according to the invention areexplained more in detail with reference to the annexed drawings.

FIG. 1 is a perspective view of a cover for the package according to theinvention, FIG. 2 is a perspective view of a carton tray of the packageaccording to the invention with part of a corner broken away, FIG. 3illustrates the blank for making the tray shown in FIG. 2, FIG. 4illustrates a corner portion of another blank for erecting the tray of asecond embodiment of the invention, all corners of the blank beingidentical, FIG. 5 is a diagrammatic perspective view of the tray cornererected from the blank in FIG. 4 partially broken and seen from theinside of the tray, FIG. 6 is a diagrammatic perspective view of thecorner in FIG. 5 seen obliquely from above and partially open beforesealing the details of the corner, and FIG. 7 illustrates anotherembodiment of the cover to be sealed to the tray in FIG. 1 or 5,respectively.

The covers shown in FIGS. 1 and 7 as well as the blank of the traysshown in FIGS. 3 and 4 consist of a cardboard or carton material whichat least on the side facing the interior of the tray has a fluid-tightcoating adapted to be sealed, which may be a plastic coating, such aspolypropylene. Text and pictures may be printed on the external sides ofthe tray and the cover. However, normally it is preferred to have aplastic coating on both sides of the tray blank in order to enablesealing by means of the plastic coating when erecting the tray.

The blank shown in FIG. 3' is by fold lines subdivided into a bottompanel 10 and four wall panels 11, I2, 13, 14. The ends of the wallpanels merge into comer portions which by means of two fold lines 16, 17are subdivided into a central sector 18 and two lateral sectors 19, 20;At each comer the angle between the fold lines 21, 22 which define theend edges of the wall panels is less than 90 so that when erecting thetray the wall panels will be obliquely inclined toward the bottom 10.This tapering shape of the tray increases the stability of the tray andfacilitates emptying thereof.

The central sector 18 has an upper extension in the form of a connectingflap 23 adapted to be folded about a fold line 24 which defines theupper edge of the central sector. Incisions 25, 26 extend through somedistances from the ends of and along the fold line 24 to provide for aspecial character of the tray in the manner described hereinbelow.

Along the outer or upper edges of the wall panels of the tray there areprovided edge flaps 27, 28 which: at their ends are beveled such thatthey fit each other upon erection of the tray and form a frame as shownin FIG.2.

In order to erect the blank, the corner portions 15 are folded inwardlyand the edge flaps 27, 28 are turned outwardly into a plane which in theerected tray is parallel to the bottom of the tray. The connecting flaps23 are turned outwardly and downwardly over the underlying end portionsof the edge flaps and are secured thereto by any suitable sealingprocess. The result is a closed frame having strong joints at thecorners. Due to the double inward folding of the corner portions suchthat the lateral sectors 19, 20 are disposed along the insides of thewall panels of the tray, corner posts will be formed at the corners ofthe tray. These corner posts are in the form of pyramids havingdownwardly pointing apexes. The connecting flap 23 is an extension ofthe central sector 18 of the respective comer'post and is secured to theedge flaps by sealing. As a result, the corner post will form a stiffstructure which can take considerable loads without being deformed.

Although the tray can be used without the incisions 25, 26, theseincisions result in an advantage because the middle portion 29 of thecentral sector 18 (FIG. 2) is located between the end of the incisionsin the central sector and can thus be pressed inwardly into a positionin which this middle portion 29 makes a substantially right angle withthe bottom of the tray which facilitates the erection of the tray in anerecting machine. The incisions 25, 26 thus make possible theillustrated pressing of the central sector 18 which is effected duringthe erection of the tray without the necessity of additional fold lines.The remaining marginal portions 30 of the central sector 18 are forcedinto tight contact with the lateral sectors 19, 20 and may be attachedto them by sealing, if desired.

As shown in FIG. 1, the cover 31 has weakening lines 32, 33 in itsplastic coated underside which extend along the margins of the cover atsuch distances as to define marginal strips 34, 35 of substantially thesame width as the edge flaps of the tray. By means of these marginalstrips the cover is sealed to the edge flaps of the tray, such as byapplication of adhesive stripes which may be heated immediately beforethe sealing operation. Instead thereof, the sealing operation may beeffected immediately after the application of the adhesive stripes andbefore these stripes have set. However, in many instances the plasticcoating on the underside of the cover and the plastic coating on theedge flaps will be sufficient to effect the necessary seal when pressedtogether and heated.

The weakening lines 32, 33 define two tear-off tabs 36. If one of thesetabs is torn off the entire cover portion 37 between the weakening lineswill be torn off whereas at least some layers of the marginal strips 34,35 remain on the edge flaps and form an additional reinforcement thereofduring the continued handling of the tray after the tray has beenopened.

In cases in which the package has to be heated it may sometimes besuitable to leave the portions below the tear-off tabs 36 unsealed so asto provide leaking gaps for vapor generated during heating of the foodproduct.

The embodiment shown in FIGS. 4 to 7 will form a package which has notcut edges facing .the interior of the closed package as in the tray inFIG. 2 where the cut edges of the incisions 25, 26 are exposed to thefood product in the tray In some instances the food product may containliquids which colours the cut edges and when this is not desired foraesthetic reasons, the embodiment in FIGS. 4 to 7 is preferred. Thisembodiment will also be more effectively sealed due to the fact that theedge flaps and the cover form a continuous sealed frame as will beunderstood from the cover shown in FIG. 7.

As shown in FIG. 4 the bottom 10 and the wall panels connected theretoand provided with edge flaps are substantially identical withcorresponding details in FIG. 3. However. the fold lines 37, 38 definingthe ends of two adjacent wall panels 39, 40 are at right angles andenclose a corner portion divided .by fold lines 41, 42 into a centralsector 43 and two lateral sectors 44, 45. At the end of the centralsector is a fold line 46 forming a hinge for a connecting flap 47 havingits sides connected with the edge flaps 48, 49 through intermediate edgeflap portions 50, 51, which are hingedly connected with the adjacentlateral sector along a fold line 52, which may be a slit if desired, andare foldable at their ends along fold lines 53, 54

for creating the tray as illustrated in FIGS. 5 and 6.

As will be understood from FIGS. 5 and 6 each corner of the tray willhave folded edges 46 and 54 which do not expose any cut edges to theinterior of the tray. Furthermore, the intermediate edge flap portions51 will contribute to the strength and sealing of the corner.

The cover to be sealed 0n the frame formed by the edge flaps 48, 49 andthe connecting flaps 47 is shown in FIG. 7 and is generally denoted by55. One side of the cover is coated with a thermoplastic layer which iscut through along a continuous incision line 56. However, the incisionhas merely a depth into the outermost layers of the carton material ofthe cover for reasons given below. At one corner a straight incisionline 57 forms a tab 58 to be used when tearing off the cover. Adjacentthe tab the incision line 56 is somewhat retracted to form an inner tab60 which is located outside the effective area of the heat sealingtools. When tearing off the cover, merely the carton layers nearest thesealed layers of plastic coating will remain, whereas the other layersof the frame outside the line will be removed together with the portionof the cover located inside the line 56. The remaining heat sealedmaterial on the edge flaps 48, 49 will form a closed frame reinforcingthe tray when the cover has been removed.

Although it is not shown in the drawings, it should be understood thatthe sealing of the cover to the edge flaps is effected upon heating andunder relatively high pressure, so that the connecting flaps 23 and 47,respectively, will be pressed substantially flush with the edge flaps toeliminate the step between the connecting flaps and the edge flaps.

If desired, the package according to the invention may also be used forfood which has not to be heated. In this case the cover may be atransparent foil.

Iclaim:

1. A package especially for food products and consisting of a cartontray closed by a cover and made from a single carton blank which on theside facing the interior of the tray has a fluid-tight coating and issubdivided by fold lines into a bottom panel and four wall panelsconnected at their ends to each other by corner portions which by meansof fold lines are subdivided into a central sector and two lateralsectors extending from a common apex at the adjacent corner of thebottom panel, characterized in that in the erected condition of the trayeach lateral sector is in contact with the adjacent wall panel of theerected tray and said adjacent wall panels define an external corner ofsaid tray and the central sector has an operative position located infront of said external corner and cooperating therewith to define acomer post of triangular cross section, the upper edges of the wallpanels of the tray have extensions in the form of edge flaps which arefolded outwardly and form a frame in a plane parallel to the bottom ofthe tray, the end portions of the edge flaps being connected to eachother by a connecting flap which is formed by an extension of the upperend of the central sector of the respective corner post and is foldedover the end portions of the edge flaps and sealed thereto, and in thatthe cover is sealed to the edge flaps and connecting flaps.

2. A package as claimed in claim 1 wherein the wall panels of the traymake obtuse angles with the bottom of the tray so as to form a conicaltray, characterized by incisions along the ends of those fold lines bywhich the central sector is articulated to the appertaining connectingflap, and in that the middle portion of the central sector locatedbetween the inner ends of said incisions has been pressed toward theadjacent wall panels into a position substantially at right angles tothe bottom of the tray, whereas the marginal portions of the centralsector have been folded into contact with the lateral sectors.

3. A package as claimed in claim 2, characterized in that the marginalportions of the central sector are sealed to the wall panels of thetray.

4. A package as claimed in claim 1 having a cover of carton materialcoated with a layer of plastic material on its underside, characterizedby an incision line having a depth to cut through the plastic layer andthrough a number of layers of the carton material, said incision linedefining the major portion of the cover located inside the edge flapsand adapted to be removed by tearing up one corner of the cover from itsconnection with the underlying connecting flaps.

